Minimalist design of water-soluble cross-beta architecture

Proc Natl Acad Sci U S A. 2010 Feb 23;107(8):3469-74. doi: 10.1073/pnas.0912654107. Epub 2010 Feb 4.


Demonstrated successes of protein design and engineering suggest significant potential to produce diverse protein architectures and assemblies beyond those found in nature. Here, we describe a new class of synthetic protein architecture through the successful design and atomic structures of water-soluble cross-beta proteins. The cross-beta motif is formed from the lamination of successive beta-sheet layers, and it is abundantly observed in the core of insoluble amyloid fibrils associated with protein-misfolding diseases. Despite its prominence, cross-beta has been designed only in the context of insoluble aggregates of peptides or proteins. Cross-beta's recalcitrance to protein engineering and conspicuous absence among the known atomic structures of natural proteins thus makes it a challenging target for design in a water-soluble form. Through comparative analysis of the cross-beta structures of fibril-forming peptides, we identified rows of hydrophobic residues ("ladders") running across beta-strands of each beta-sheet layer as a minimal component of the cross-beta motif. Grafting a single ladder of hydrophobic residues designed from the Alzheimer's amyloid-beta peptide onto a large beta-sheet protein formed a dimeric protein with a cross-beta architecture that remained water-soluble, as revealed by solution analysis and x-ray crystal structures. These results demonstrate that the cross-beta motif is a stable architecture in water-soluble polypeptides and can be readily designed. Our results provide a new route for accessing the cross-beta structure and expanding the scope of protein design.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amyloid beta-Peptides / chemistry
  • Crystallography, X-Ray
  • Hydrophobic and Hydrophilic Interactions
  • Models, Molecular
  • Peptides / chemistry*
  • Protein Engineering / methods*
  • Protein Folding
  • Protein Structure, Secondary
  • Solubility
  • Water / chemistry*


  • Amyloid beta-Peptides
  • Peptides
  • Water